The present invention relates to a housing for an axial-type compressor which will accommodate the expansions and contractions of the compressor, and a process for manufacturing the housing.
Axial gas turbine engine compressors typically have a rotor wheel assembly having a plurality of stages of rotor blades mounted thereon. Such compressors also incorporate several rows of stator vanes which are disposed between the rotor blades in a longitudinal direction. The stator vanes are rigidly affixed to an outer envelope or housing that forms part of the compressor case.
French Pat. No. 2,482,661 as well as U.S. Pat. Nos. 4,431,373 and 4,426,191 disclose typical examples of such a gas turbine compressor wherein the stator vanes are attached to an inner shell formed of peripheral segments and which, in turn, is attached to an outer shell by radial flanges. The radially inner ends of the stator vanes are joined to an inner collar and the stator assembly is surrounded by an air cooling manifold.
Other examples are shown in French Pat. No. 2,534,982 and U.S. Pat. No. 4,543,039 wherein the segments of the inner shell are hooked or otherwise fastened to an outer shell to form the compressor case. U.S. Pat. No. 4,696,619 provides the compressor housing with a plurality of longitudinally extending pins to attach the inner shell segments to the outer shell.
The object of these known systems is to maintain a slight, but constant clearance between the rotor and the stator regardless of the operating conditions of the gas turbine engine. This is of particular importance during the transitional stages of acceleration and deceleration to maintain acceptable levels of engine performance, efficiency and specific fuel consumption. Although the known examples may achieve these improved results, their implementation serves to increase the complexity of the engine structure and increases the difficulty of assembly and disassembly due to the large number of parts involved. This complexity also serves to increase both the cost of the compressor and the weight of the assembled engine.